You Only Need £1000 To Get Into Property | Maximising Profit Using Serviced Accommodation 

What you're missing, is that they haven't signed the usual residential rental agreement. They will not be living there, they will be providing accommodation to other people, so they have signed either a Commercial Lease or Management Agreement, both of which will have a clause in there, that specifically allows rental of the property on a per-night basis to clients of the company that has signed the lease/agreement.

Its done with a management agreement rather than a standard lease